/* boot.S - bootstrap the kernel */
/* Copyright (C) 1999, 2001  Free Software Foundation, Inc.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#define ASM_FILE        1
#include <multiboot.h>

/* C symbol format. HAVE_ASM_USCORE is defined by configure. */
#ifdef HAVE_ASM_USCORE
	# define EXT_C(sym)                     _ ## sym
#else
	# define EXT_C(sym)                     sym
#endif

/* The size of our stack (16KB). */
#define STACK_SIZE                      0x4000

/* The flags for the Multiboot header. */
#ifdef __ELF__
	# define MULTIBOOT_HEADER_FLAGS         0x00000003
#else
	# define MULTIBOOT_HEADER_FLAGS         0x00010003
#endif

        .text

        .globl  start, _start
start:
_start:
        jmp     multiboot_entry

        /* Align 32 bits boundary. */
        .align  4

        /* Multiboot header. */
multiboot_header:
        /* magic */
.long   MULTIBOOT_HEADER_MAGIC
/* flags */
.long   MULTIBOOT_HEADER_FLAGS
/* checksum */
.long   -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)

#ifndef __ELF__
/* header_addr */
.long   multiboot_header
/* load_addr */
.long   _start
/* load_end_addr */
.long   _edata
/* bss_end_addr */
.long   _end
/* entry_addr */
.long   multiboot_entry
#endif /* ! __ELF__ */

multiboot_entry:
        /* Initialize the stack pointer. */
        movl    $(stack + STACK_SIZE), %esp

        /* Reset EFLAGS. */
        pushl   $0
        popf

        /* Push the pointer to the Multiboot information structure. */
 		pushl   %ebx
 		/* Push the magic value. */
        pushl   %eax

        /* Now enter the C main function... */
        call    EXT_C(cmain)

        /* Halt. */
        pushl   $halt_message
        call    EXT_C(printf)

loop:   hlt
        jmp     loop

halt_message:
        .asciz  "Halted."

         /* Our stack area. */
.comm   stack, STACK_SIZE
